http://en.wikipedia.org/wiki/DARPA_Grand_Challenge shows Stanford and Carnegie Mellon switching places between the 2005 and 2007 versions. Also, in both cases, I would say the top three are so close together that chance may have affected the rankings more than 'being ahead'. For example, if the course would have been slightly different (tighter corners, different road signage, whatever), would the teams have finished in the same order? Also, in both challenges, I would say the third-placed team had similar performance as the top two.

So no, I do not think that that shows Google is far ahead of the field. Or did Google hire both teams? Even that would not totally convince me., as it looks as if only US teams took part in those races.